US2821378A

US2821378A - Tapping device for molten metals

Info

Publication number: US2821378A
Application number: US490940A
Authority: US
Inventors: Tama Mario
Original assignee: Ajax Engineering Corp
Current assignee: Ajax Engineering Corp
Priority date: 1955-02-28
Filing date: 1955-02-28
Publication date: 1958-01-28
Anticipated expiration: 1975-01-28

Description

Jan. 28, 1958 M. TAMA 2,821,378

TAPPING DEVICE FOR MOLTEN METALS 2 sheets-'sneer 1 y Filed Feb. 28, 1955 AcruATlN' IN V EN TOR.' MAmo TAMA,

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Jan. 28, 1958 M. TAMA TAFPING DEVICE FoR MOLTEN METALS 2 Sheets-Sheet 2 Filed Feb. 28, 1955 INVENTOR- MAmo TAMA,

United l States Patent O TAPPING DEVICE FOR MOLTEN METALS Mario Tama, Morrisville, Pa., assignor to Ajax Engineering Corporation, Trenton, N. J., a corporation of New Jersey Application February 28, 1955, Serial No. 490,940

Claims. (Cl. 266--42) The invention relates to furnaces for molten metal and relates more particularly to tapping devices for the control of the outlet of molten metal from such furnaces.

Heretofore, the conventional method of tapping metals from such furnaces was to provide the furnace with a tapping hole at or near the bottom of the furnace and closing the hole temporarily with clay or similar material. This temporary closure was opened with the aid of a rod and then the metal permitted to ow out in a stream, in` most instances into a ladle, until either the furnace was emptied or a new closure made by introducing a ball of re clay into the tapping hole by means of a rod.

lt has been proposed to provide other means for tapping melting pots or furnaces, but these attempts have not been successful for use with metals of highmelting point such as aluminum, steel, brass and the like, as the mechanisms of these proposals are subject to dissolution by the prevailing contact with the high temperature molten metal.

The instant invention has among its objects the provision of a tapping device that may be used with high temperature molten metals and be opened and closed at will without destruction to the closure, and which will promote a continuous and free ow easily controllable so that the metal may directly 'be discharged into a mold.

This application is a continuation-impart of my copending application Serial No. 29,263 that was filed on May 26, 1948, now Patent No. 2,707,718, dated May 3, 1955.

Fiurther objects and advantages of the invention will be set forth in part in the following specication and in part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following;detailed description, taken in connection with the accompanying drawings, in which: i

Fig. 1 is a plan view of a furnace for molten metal having a tapping device in accordance with the invention;

Fig. 2 is a sectional View taken on line 2--2 of Fig. l;

Fig. 3 is a large-scale fragmentary sectional view showing a detail of the tapping device; and

Fig. 4 is a fragmentary sectional View, similar to Fig. 3, but embodying a modication.

In carrying the invention into eiect in the embodiments which have been selected for illustration in the accompanying drawings and for description in this specification, and referring now particularly to Figs. l and 2, there is provided a furnace for molten metal generally indicated at 11, which may either be a metal furnace or a holding furnace.

The furnace 11 is lined with refractory material 12 along the side wall 13 and the bottom 14, and Ihas heating means generally indicated at 16 which may be of the induction type such as described in my Patent No. 2,539,800, issued January 30, 1951.

The furnace 11 may, in accordance with a preferred embodiment, be tiltable about a pivot 17 that acts as a 2,821,378 Patented Jan. 28, 1958 ICC fulcrnm. This tilting has the advantage for completely emptying the furnace 11 when desired by tilting in the direction 18 and also for tilting it back in a direction 19 to free the tapping device from contact with molten metal, should that be desired While metal is still in the furnace.

A tapping device generally indicated at 21 is provided in the side wall 13. It comprises a tube 22 that is sealed into an inclined bore 23 that is formed in the side Wall 13. The tube 22 forms with the horizontal an acute angle and extends through the wall 13 'upwardly and outwardly in respect to the metal chamber 24 of the furnace 11. The tube 22 is open at its lower end 26 and at its upper end 27, and is constricted near the lower end 26. The lower end 26 Ihas an inlet 28 that has a smaller crosssectional area A than the interior cross-sectional area B of the remainder of the tube 22.

A constriction is provided by an annular apertured valve seat element 29 that is formed near the inlet 28; the element 29 has an area C of aperture that is smaller than the area B, and it has an annular conical surface 31, which surrounds the aperture of the element 29 and faces the upper end 27, and that surface 31 defines a valve seat. A valve closure element such as a stopper 32 fits against said valve seat 31, and is carried at the end of a rod 33. The rod 33 is movable axially of the tube 22 n in

opposite directions

34 and 36 towards and from a valve closure position wherein the stopper 32 engages the seat 31. The valve seat 31 is immersed in the molten metal not only during pouring but also during the time intervals between .the pours.

The tube 22 is made of heat resistant material, such as refractory material, for instance silicon-carbide, or of similar suitable material. The stopper 32 and the valve seat element 29 are made of heat resisting material, for instance graphite or carbon. The rod 33 may be made of steel or cast iron but is covered at least throughout that portion which reaches into the tube 22 by a layer 37 of heat resistant material, such as refractory material or a coating of suitable material such as for instance material known under the trade-name or trade-mark Spattershield.

A solenoid, generally indicated at 38, may be carried by a bracket 40 attached to the side wall 13, in such a manner that the armature of the solenoid 38 is connected to the rod 33. Furthermore, a spring 39 may be arranged to bias the rod 33 towards return to its normal position wherein the stopper 32 engages the valve seat 31. The leads of the solenoid 38 may be connected to an actuating device 41, s-uch as a push button or a timer (not shown in detail) in order to control the solenoid 38 and thereby the rod 33 and stopper 32. Upon energization of the solenoid 38, it will remove the stopper 32 olf the valve seat 31, against the bias of the spring 39; upon deenergization, the solenoid 38 will release the rod 33 to be returned to its normal position under the impulse of the spring 39 to cause valve closure. i

The upper portion of the tube 22 is surrounded by an electric heater coil 42 that may be energized to prevent freezing of the metal in the tube 22. When the valve is closed, the metal stands in the tube 22 at the level 43, close to the lower tip of the upper end 27. The metal level 44 in the chamber 24 is normally higher than the metal level 43 causing, upon opening of the stopper 32, a free flow of the molten metal outwardly 'through the upper end 27 of the tube 22. A mold 46 may be positioned below the outpouring stream of molten metal for direct 'discharge of the molten metal into the mold 4.6,- as best shown in Fig. 2.

A steel jacket 47 is provided around the upper `portion of the tube 22 and is spaced therefrom, forming an annular space 48 that may be filled with insulating material, for instance plastic insulation 49.

In the modification shown in Fig. 4, there is provided a removable unit 50 that comprises a cover plate 141 which is surrounded by a steel jacket 147; the steel jacket 147 is applied against the side wall 113 of the furnace 1111 and may removably be secured thereto, for instance by' screws 52 applied to a iiange 53 of the steel jacket 147. The cover 51 has an inclined bore 123 into which is sealed the tube 122. The chamber 124 of the furnace 111 hasl a channel 54 into which the tube 122 reaches, dipping into the molten metal that lls the channel 54, and the cover plate 51 is applied to close the channel 54.

A space 148 is provided between the steel jacket 147 and the tube 122, and insulating material 149 and a heater coil 142 are located in that space 148. The bracket 140 may be attached to the cover 51; the other parts, the rod 133, the stopper 132, and the valve seat 131, operate in the same way as in the previously described embodiment.

The operation of the above described invention is as follows.

Energization of the solenoid by the actuator 41 will remove the stopper 32 of the valve seat 31, and molten metal will flow from the chamber 24 through the tube 22, and will be discharged in a free flow off the lower tip of the open end 27 of the tube 22. The molten metal owing into the tube 22 through the aperture of the valve element 29, which forms a constriction relative to the interior cross sectional area B of the tube 22, will ow easily and continuously from the chamber 24 into the tube 22. The constriction which is immersed in the metal bath promotes continuous flowing by preventing build-up, and this is apparently caused by the rapid flow through the constriction. The metal emerging from the tube 22 in a free ow may be directed to be discharged directly into a mold 46. Upon deenergization of the solenoid 38, the spring 29 will return the stopper 32 to close the valve; similarly, upon power failure, the solenoid will be de-activated and the spring 39 will act to close the valve in the same manner.

As best shown in Figs. 3 and 4, the tube 22 (122) is during the intervals between pours iilled with molten metal to the level 43 near the pouring lip, so that upon lifting of the stopper 33 (133) the tube will substantially without delay start pouring the metal in a free gentle parabolic flow, for instance into the mold 46.

The furnace 11 may be tilted about the fulcrum 17, either in direction 18 when the metal level 44 has become too low for normal gravitational discharge through the tube 22 in the normal position of the furnace 11, or be tilted in direction 19 to free the lower end 28 of the tube 22 from contact with molten metal.

It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific exemplications thereof will suggest various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific exemplilcations of the invention described herein.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent, is as follows:

1. In a tapping device, for use in connection with a furnace for molten metal having a bottom and a side wall defining a chamber for the molten metal bath, in combination, a tube having a solid uninterrupted encircling wall and being open at both ends protruding through said side wall and being inclined at an angle to the horizontal plane and adapted to extend with its lower end into the metal bath in said chamber and with its upper end to the exterior of said furnace, said tube being composed of heat resistant material and having near itslower end a constriction, a valve seat formed near said constriction on the tube interior and adapted to be immersed in the molten metal during pouring and during the time intervals Ibetween pours, and a stopper on the interior of said tube movable Within said tube in opposite directions to and from said valve seat for releasably sealing the same and including a stem extending from said stopper through said open upper end to the exterior of said tube, the molten metal filling said tube between pours to a level slightly below the pouring level and below the level in the furnace, whereby upon removal of said stopper off said seat molten metal may ow upwardly through said tube and thereafter in a free constant flow emerge from the upper end of said tube.

2. In a tapping device, as claimed in claim 1, together with, heating means surrounding at least the upper portion of said tube for restraining metal freezing therein.

3. In a tapping device, as claimed in claim 1, together with, a metal casing surrounding at least the upper portion of said tube and spaced therefrom dening with the exterior of said tube portion an annular space, and insulating material disposed in said space.

4. In a tapping device, as claimed in claim 1, together with, means operatively connected to said stem and operable for guding said stopper to and from its sealing position on the valve seat, resilient means actuatable to urge said stopper towards said seat for normally closing the valve, and a mechanism energizable to move said stopper away from said valve seat against the bias of said resilient means and arranged to release said stopper upon deenergization for return thereof under the impulse of said resilient means.

5. In a tapping device unit, for use in connection with a furnace for molten metal including a bottom and a side wall dening a chamber for the molten metal bath including a lateral channel formed in said side wall below the normal metal level, in combination, a side cover secured to said side wall adjacent said channel and having a larger dimension than the cross-section of said channel to close the same throughout, said cover comprising a wall having a bore inclined upwardly when said wall is positioned on said furnace intercommunicating with the interior of said channel, a refractory tube disposed in said channel and open at both ends and extending with its upper end to the exterior of said wall and extending with its lower end into said channel, said lower end being in said channel immersed in the molten metal bath, and having a constriction and adapted to be immersed in the molten metal bath, a valve seat formed near said constriction, and a stopper movable on the interior of said tube in opposite directions to and from said seat for releasably sealing the same and including a stem extending from said stopper through said open upper end of said tube to the exterior, the molten metal filling said tube between pours to a level slightly below the pouring level, whereby upon removal of said stopper oif said seat molten metal may ow upwardly through said tube and thereafter in a free constant ilow emerge from the upper end of said tube.

References Cited in the le of this patent UNITED STATES PATENTS 1,027,821 Cunningham May 28, 1912 1,162,246 Menough Nov. 30, 1915 2,112,161 Kelly Mar. 22, 1938 2,426,644 Van der Pyle Sept. 2, 1947 2,535,335 Thevenin Dec. 26, 1950 2,587,727 Horswell et al. Mar. 4, 1952 2,676,011 Loftus et al Apr. 20, 1954 2,678,480 Lapin May 18, 1954 2,713,705 Lapin July 26, 1955 2,745,153 Burkett May 15, 1956 FOREIGN PATENTS 702,833 Great Britain Jan. 27, 1954